Maintenance Tips

To keep your Yo-Yo in top condition you always have to consider the following three points:

The bearing
The string
The responsesystem

1.The bearing

The way you have to treat your bearing varies from playstyle to playstyle.
Here's a rule of thumb:
For all playstyles involving stringtricks (1A,3A,Offstring und Freehand) you want to have your bearing to spin for a long time. You achieve this with a clean bearing, free of oil, dust, or other residues. If any residues are left inside the bearing or if you oiled the bearing too much, (there is nothing wrong with using thin oil e.g. Jam Lube thin if one likes it responsive) you will have to clean the bearing.
The procedure is pretty simple: You take any kind of solving liquid e.g. pure alcohol or gas (personally I'm using gas for lighters) pour some of it into a small container and let the bearing soak in the liquid, 10 minutes should be enough, but if you really want to get all of the residues out of the bearing, let it soak over night. There is a trick, for those in a hurry: You can use a film container and shake the bearing inside the liquid. Now let the bearing dry for about 5 minutes on a paper towel and then, put it back into the yo-yo. If the bearing should not be as clean as you want it, rinse and repeat the procedure. Now oil the bearing drop by drop to your liking and you are ready to go.

AA yo-yos will have to come back way easier and snappier than A yo-yos. So check the responsesystem first and if that is still intact, it is time to oil the bearing. Do this in the same manner you would do for a A yo-yo after cleaning, although I'd advise you to use thicker oil e.g. Jam Lube thick, because you want to have more response for looptricks, as I already mentioned.

2.The string

This part is easy to check: If the string changes it's color to shades of gray or if the feeling of the string gets worse (e.g. the string does not slide on your fingers as easily), it is definitely time to change your string. You also want to immediately change it, if you got yourself a bad knot, which you can not open again or naturally, when the string breaks (which most of the time happens when the string has been used for too long).
Changing your string is not only important for your yo-yos performance, but also for safety. It is definitely more adequate to invest around 14 Eurocent into one new string, then to see your new favourite yo-yo fly 50 metres through the air and then hit concrete.. (that happened to my 2nd ball-bearing yo-yo back in 1998 ;) ).

3.The responsesystem

Here you will have to distinguish between starburst, hybrid-, o-ring- or pad-resonse.
The three first systems require little to no maintenance (there are only a handful of players who can play thorugh o-rings), whereas yo-yos with pad-response (e.g. Alchemy MX or all Dif-e-Yos) will require a new pad every now and then. You can tell when this time comes, if the string is not being tightly gripped by the pad and "slips through" at the end of a throw or on a bind."